Some track assemblies of track-type machines include a pair of parallel track chains, which include a plurality of links that are interconnected by laterally disposed pins. A bushing is disposed about each pin such that it can rotate relative to the pin and the links. The bushings are engaged by a drive sprocket that propels the track assembly. Specifically, the track assembly is rotated about guide rollers and an idler. As the track assembly rotates, it engages a ground surface and propels the machine. Unfortunately, rotating the track assembly about the idler can cause undesirable noise and link wear.
One way to reduce noise caused by rotating a track assembly about an idler is to reduce direct contact between the track assembly and the idler. An example of this strategy is described in U.S. Patent Application Publication No. 2005/0253453 A1 (the '453 publication) by Miller, published on Nov. 17, 2005. The '453 publication describes an idler wheel including a plurality of axially spaced annular rims. A first and a second one of the rims are arranged on opposite sides of the idler wheel. These rims, which have substantially equal diameters, support and guide links of a chain about the idler wheel. A central rim, having a larger diameter than the first and the second one of the rims, is positioned between the first and the second one of the rims. And, an elastomeric ring circumferentially surrounds the central rim. The elastomeric ring is adapted to directly and resiliently engage pin and bushing assemblies, thereby reducing contact noise between a track (including links that are interconnected by the pin and bushing assemblies) and the idler wheel as the track rotates about the idler wheel.